Froth flotation of acidic minerals



I Patented June 8, 1943 UNITED Ludwig Jacob Christmann, Yonkers, N. Y., and David Walker-Jayne, In, Old Greenwich. and

Stephen E. Erickson, Springdale, Conn as-' signors to American Cyanamld Company, New York, N. Y., a corporation of Maine No Drawing. Application September 4, 1940,

Serial N 355,366

7 Claims. (chaos-16s) The present invention relates to mineral concentration. More particularly it relates to a v new class of reagents for selectively separating acidic minerals from ore materials.

This application is in part a continuation of our application Serial No. 326,952, filed March 30, 1940.

In accordance with this invention natural ores or artificial materials comprising mixtures of acidic minerals with other mineral constituents are-subjected to a separation or concentration process in the presence of a promoter of the class comprising the condensation products obtained by reacting one molecular equivalent of a polyalkylene polyamine with two molecular equivalents of a fatty acid, or the salts of such minerals from the other ore constituents. Particularly this invention relates to the use of the diacidyl reaction products of polyalkylene polyamines with fatty acids, fatty acid glycerides or other esters, either as the free base or as the substantially water-soluble salts of such products, as promoters orcollectors for acidic minerals in froth flotation, film flotation, stratification,

agglomeration, tabling, and related mineral sepaacid glycerides or other esters, and salts of these reaction products. These compounds are, in general, surface active and are basic in character.

, A general method of preparing the above reagents comprises heating two molecular equivaproducts, to effect a separation of the acidic v bon radical and Y' 'is a short chain hydrocarbon radical '1 mol. of a polyalkylene is reacted with a mixture comprising 1 mol. of a long chain fatty acid and 1 mol. of a short chain fatty acid.

The products are usually homogeneous viscous pastes which are soluble in aliphatic alcohols or other organic solvents. They combine with acids such as formic, acetic, hydrochloric, and the like to yield salts which are soluble in water.

These diacyl derivatives of the polyalkylene polyamines are those most probably represented by the following generalformula:

YCO-NH-AOCY' wherein A represents the group or a plurality of such groups serially arranged, R. and R1 represent hydrogen or alkyl radicals, Y represents an aliphatic hydrocarbon radical containing at least 9 carbon atoms which hydrocarbon radical may contain oneor more double bonds and may be substituted by hydroxy groups, Y represents an aliphatic hydrocarbon radical, which hydrocarbon radical may contain one or more double bonds and may be substituted'by hydroxy groups, and the salts of such compounds.

Representative polyalkylene polyamines which may be" employed in condensing with the fatty acids are diethylene triamine, dipropylene triaminepdibutylene triamine, triethylene tetrafrom 2 to 12 carbon atoms. It is an advantage lents of a fatty acid, or an amount of fatty acid g-lyceride sumcient to yield the equivalent of 2 mols. of the fatty acid, with one molecular equivalent of a 'polyalkylene polyamine at a temperature of about.230-240 C. until the reaction is complete. The compounds produced by the above are the type represented by the general of the present invention that relatively crude mixtures of the various polyamines may be used for reacting with the fatty acids or fatty acid glycerides which results. in the production of reagents at a lower cost than possible by using the purified polyamines. For example, when based on the saponiiication value of cottonseed oil and the average molecular weight of a crude mixture of polyethylene polyamines, a ratio of approximately 20 parts of amine to parts of oil will yield a product consisting essentially of diacyl derivatives. The product so produced is suitable for use as a silica promoter and it is not necessary to remove the glycerin split off by the reaction.

Either the saturated, unsaturated, or hydroxy fatty acids and fatty acid glyceride having at invention.

least 9 carbon atoms, may be employed for reacting with the polyamines. Representative acids and fatty acid glyceridesinclude lauric, palmitic, stearic, oleic, ricinoleic, capric, and cyristic, mixtures of such acids or glycerides and especially,

palm kernel oil, cottonseed oil, corn oil, linseed oil, olive oil, peanut oil, fish oils, and the like. The fatty acids or glycerides described above maybe replacedin part by short chain aliphatic acids; such as, formic, acetic, propionic, butync, va1eric; caproic, heptoic, octoic, lactic, hydroxybutyric, etc., to produce compounds in which Y is a short chain hydrocarbon radical and Y is a long chain hydrocarbon radical.

The promoter action of the reagents of the present invention will, of course, vary with different acidic ore materials and with the different polyalkylene polyamine fatty acid condensation products or salts used. For example, with the diacyl polyalkylene polyamines produced from fatty acid glycerides in which the average molecular weight of the fatty acids is comparatively low, such as those of coconut oil and palm kernel oil, the best results are obtained when such compounds are used in the form of their waterfor the flotation of feldspar from quartz and for the flotation of mica from quartz and calcite.

The reagents of the present invention may be used alone or in mixtures with other promoters.

til

soluble acid addition salts, for example, the

acetates. When the diacyl polyalkylene polyamine is produced from fatty acid glycerides the average molecular weight of the fatty acids of which is relativelyhigh, such as those of cottonseed oil, they give the best results when used in the form of the free base.' Therefore, it is not necessary in the presentinvention to use watersoluble salts, and the compounds in the form of the free base may beused provided satisfactory dispersion and distribution is effected. In the froth flotation operations, dispersion may be effectively obtained by feeding an alcoholic solution of the compound into the flotation circuit or by the use of emulsions containing the reagents from' non-metallic ores in which the siliceous gangue may represent a much smaller proportion of the ore rather than metallic and sulfide ores in which the gangue usually represents the major proportion of the ore. Representative acidic ore materials are the feldspars, quartz, pyroxenes, the spinels, biotite, muscovite, clays, and the like.

While as stated heretofore, the present invention is not limited to the treatment of any particular ore materials, it has been found to be well suited for froth flotation of silica from phosphate rock, and this is a preferred embodiment of the In the processes of removing silica from phosphate rock the conditions are such that practically complete removal of the silica must be accomplished in order to produce a salable phosphate material. It is therefore. an advantage of this invention that our reagentsnot only ef-* fect satisfactory removal of the silica but are economical in amounts used. The quantities required range from 0.1 pound to 2.0 pounds per ton of ore depending upon the particular ore and the particular reagent. The invention is not, however, limited to the use of such quantities.

These reagents have alsobeen successfully used They may likewise be used in conjunction with other cooperating materials such as conditioning reagents, activators, frothing reagents, depressing reagents, dispersing reagents, oily materials such as. hydrocarbon oils, fatty acids or fatty acid esters.

a These new reagents are also adaptable for use in any of the ordinary concentrating processes such as film flotation, tabling, and particularly in froth flotation operations. The ore concentrating processes employed will depend upon the particular type or kind of ore which is being processed. For example, in connection with phosphate rock, relatively coarse, phosphate bearing material, for example 28 mesh and larger, can be economically concentrated by using these reagents in conjunction with other materials such as fuel oil or pine oil and subjecting to concentration by the use of tables or by'film flotation. The 28 mesh phosphate rock material is best concentrated by means of froth flotation employing these improved silica promoters.

When the reagents of the present inventionare employed as promoters in the froth flotation of silica from phosphate rock the conditions may be varied in accordance with procedures known to those skilled in the art. The reagent may be employed in the form of aqueous solutions, emulsions, mixtures, or solutions in organic solvents such as alcohol and the like. The reagents may be introduced into the ore pulp in the flotation cell without prior conditioning or they may be conditioned with the ore pulp prior to the actual concentration operation. They may also be stage fed into the flotation circuit. a I

Qther improved phosphate flotation features which are known may be utilized in connection with the present invention such as the very complete removal of the slime prior to flotation which is an aid to better results, as pointed out in the Erickson application Serial No. 325.611, filed March 20, 1940, and the Mead and Maust application serial No. 320,121, filed February 21, 1940,

which describes a proces for classifying and desliming phosphate flotation feed by means of a hindered settling classifier and which deslimed feed is well suited for treatment in accordance with this invention. g

The invention will be further illustrated by the following specific examples which are illustrations .of the preferred embodiments thereof, but it is not intended to limit the; invention thereby.

EXAMPLE Flotation tests as follows were made on a sam- I Separate 600 gram samples of deslimed flotation feed were diluted to 22% solids with water and transferred to a laboratory size Fagergren flotation machine. The particular reagent or reagent combination was then added and conditloned with the pulp for 3 seconds. Air was admitted to the machine and the resultant concentrate was skimmed of! for 2 minutes. The flotation test products were then filtered, dried,

v I 2,321,130 weighed. and assayed. The metallurgical data the limits of reasonable experimental error.'

ed on this type of are the rough tailing resulting from the flotation of silica, containing both magnetite and llmonite, assayed much higher in iron than concentrates produced by the conventional soap flotation of the iron minerals.

We claim:

-1. In the froth flotation process of separating ble I phosphate ore values from acidic siliceous gangue m h the step which comprises subjecting the ore to 8 355, 3? 10 froth flotation in the presence of a reagent-comgas. v RcragerlitzghDliacidyllreaction r oguot I prising the diacidyl reaction products of a polyo. p re y ov s a Weight 1,150]; alk lene polyamine represented by the following (per cen (per cent) general formula:

1 2s 43 '1 H 0 H N H 1 30171 2:41 '\N( -C..H1..N/ a 28.52 2.31 n 4 29.34 2.10 n 5 32.50 2.82 g d g gif: in whichn, m, and a: are small whole numbers 3 Oleic acid" 37: with cottonseed O11. I w 2. In the froth flotation process of separating I All reagents used as the free base and fed as a solution in ,a mixphosphate Values foul-acidic 5111680115 gansue ture oi'aliphaticalcohols having from 7-10 carbon atoms. (0.8lb./tou the step which comprises subjecting the ore t0 froth flotation in the presence of a reagent c'om- Another series of, tests was run on a' different prising the ,diacidyl reaction products of a polysample of phosphate rock from the Old Colony alkylene P y e presented by e ol E mine. The testing procedure, scrubbing, deslirngeneral formula! ins, and flotation used for this-series of tests was n H the sameasthat followed in the previous test. f) The metallurgical data obtained in these tests v H are found'in Table II. H H

Table If v I LbJion feed I gg smg Test Diacidyl reaction product of polyethylene Added BS No. polyamines and- 7 High;

Proalcohol -Wsight Per cent motor mm" (per cent) insol- 1 Cottonseed on 43% soln. in a mix. or aliphatic alcohols 0.9 1.2 22.33 1.10

' (7-l0 carbon atoms). p 2 Cottonseed oil 43% soluin a mix. of aliphatic alcohols 0.6 0.3 28.43 1.4a

- (7-10 carbon atoms); 1 3 Cottonseed oil 43% soln. i a mixof aliphatic alcohols 0.5 0.67 29.40 2.16 (7-10 carbon atoms). 4 Cottonseed oi1 43% soin. in a mix. of aliphatic alcohols 0.4 0.53 32.05 2.70 7-10 carbon atoms). 5 Cottonseed oil 25%soiminisopropyl alco ol 0.4 0.12 37.58 2.73

An analysis of the metallurgical data found in TablesI and II shows that in all tests the phosphate product (tailings) is of a satisfactory marketable grade, and'that the phosphate product is a better grade than that currently produced .by the flotation of phosphate particles from the quartz.

the phosphate ores.

While the above examples relate specifically to than would be obtained in the soap flotation of the flotation of'silica from phosphate rock, the

present invention is not limited to such operations and the reagents used are useful in the treat ment of various other types of ore materials wherein it is desirable to remove acidic minerals in the froth. For example, the reagents are use- 111 in the treatment of the rake sands from the tailings produced in cement plant operations. In this particular instance the rake sands are treat ed by flotation to remove part of the alumina which is present in the form of mica and the re-' moval of silica is not desirable. Our reagents In most of the tests the recovery of a satisfactory phosphate product is much higher in which n, .m, and rare small l In test 5 the frother used was 0.121b. of pine oil per ton, and in addition l1) lbs. of isopropyl alcohol per ton were added with the promoter.

- prising the diacidyl reaction products of a poly-v alkylene polyamine representedby the following general formula:

v whole numbers with corn oil.

4. In the froth flotation process of separating phosphate ore values from acidic siliceous gangue the step which comprises subjecting the ore to froth flotation in the presence of a reagent produced by reacting cottonseed oil with a mixture oi -polyethylene polyamines, represented by the following general formula:

11 H I \N (CH| CHI-N CH H J H/ A). 2-0 r-N\ in which :1: is a small whole number in a proporin which a: is a small whole number in a proportion such that the diacidyl polyethylene polyamine derivative is produced.

6. In the froth flotation process of separating phosphate ore values from acidic siliceous gangue the step which comprises subjecting the ore to.

froth flotation in the presence of a reagent produced by reacting corn oil with a'mixture of polyethylene polyamines, represented by the following general formula:

/H I )-er1, CHr-N\ CHrCHr-N in which a: is a small whole number'in a propor- I ,tion such that the diacidyl polyethylene polyamine derivative is produced.

'1. In the froth flotation process of separating non-metallic ore values from acidic silicious gangue the step which comprises subjecting the ore to froth flotation in the presence of a promoter for the acidic silicious gangue, said promoter being chosen from the group consisting of the mixture of reaction products obtained by reacting substantially 2 equivalents of a fatty acid glyceride in which the fatty acid radical of said glyceride has at least 10 carbon atoms with substantially one equivalent of a polyalkylene polyamine represented by the following general formula:

in which n, m, and a: are small whole numbers, and salts of such products.

LUDWIG J. CHRISIMANN. DAVID WALKER JAYNE, JR. S'I'EPHEN n. ERICKSON. 

